Spark-plug.



L. P. McKEONE.

SPARK PLUG.

APPLICATION FILED JAN. 15. I916.

mfi wflfiw Patented Aug. 21, 1917 l f. 5.1 1 1 hi i 4 I 1 1 lAll/E/VTOR LAWRENCE P. MGKEONE, OF NEW YORK, N. Y.

SPARK-PLUG.

Specification of Letters Patent.

Patented Aug. 211, 1917.

Application filed January 15, 1916. Serial No. 72,205.

To all whom it may concern Be it known that I, LAWRENCE P. MoKEoNn, a citizen of the United States, re-

siding at the city of New York, borough of wiping the electric terminals in a manner to remove therefrom any accumulation of carbon which otherwise would have a tendency to interfere, and to a substantial extent, with the spark in jumping from one terminal to the other, and, second, means are provided whereby after adjustment of one terminal relatively to the other in order to compensate for a reduction in the operative length of the terminal, one of said terminals may then be returned to such a position that the spark gap separating the two said terminals will be of a predetermined length, thus enabling the spark plug to be maintained in a condition assuring maximum efficiency.

It is well known to those skilled in the art that spark plugs using two terminals, one of which is composed usually of platinum or a platinum alloy, or a similar metal, are subject to deterioration by the heat of the en.- gine, resulting in the course of time in a decrease in the operative length of that terminal which extends toward the other terminal. This variation in the spark gap, and the accumulation of carbon deposits upon the terminals, is a source'of serious objection, resulting in decreased efliciency and failure to ignite the charges.

So far as I am aware, no provision has heretofore been made for remedying the foregoing and other difliculties, and it is the object of my invention to produce a plug of simple and economical construction wherein the foregoing objections are eliminated, a

characteristic feature of the plug being the adaptation of the parts whereby all the necessary adjustment may be made while the plug remains at'ached to the engine cylinder, or while the motor is in operation, so

that it is not necessary to detach the plug either for cleaning purposes or to'adjust the spark gap terminals relatively toeach other.

Other features of the invention, and the advantages thereof will be apparent from the foregoing description taken in connection with the drawings.

In the drawings,

Figure 1 is a vertical section through a spark plug embodying my invention, the parts being shown in their normal positions.

Fig, 2 is a side elevation of the spark plug illustrated in Fig. 1.

Fig. 3 is a sectional plan view on the line 3-4-3 of Fig. 1.

Fig. 4 is a horizontal section on the line 1 l of Fig. 1.

Fig. 5 is a sectional plan view similar to Fig. 3, but showing the parts adjusted to a position for short circuiting the current through the spark gap terminals.

Fig. 6 is a horizontal section similar to Fig. 4 with the spark gap terminals in a position corresponding to Fig. 5 so as to short circuit the current.

The spark plug of my invention embodies a body member 10'composed of porcelain or other electrical insulating -material. Said body 10 is provided intermediate its ends with an enlargement 11 constituting an upper shoulder and a lower shoulder. Below the enlargement, the insulating body 10 is cut away internally thereof so as to produce an internal shoulder 12 and an extension 13 depending below said internal shoulder 12, the internal diameter of the extension 13 being larger than the corresponding diameter of the opening through the body 10, all as clearly shown in Fig. 1

Cooperating with the insulating body is a nut member .14, the internal diameter of which slightly exceeds the enlargement 11, so that the enlarged part of the body 10 will fit snugly within the attaching nut 14. The lower part of the attaching nut 14: is reduced in diameter and is externally threaded at 15. Below the threaded part 15 of the attaching nut there is formed a ring 16, said ring16 being integral with the material of the attaching nut 14, and, said ring being constructed to serve thefunction of one of the spark gap terminals. The attaching nut 14: is provided intermediate, the spark'gap terminal ring 16 and the threaded attaching part 15 with a plurality of slots 17, preferably two in number, as shown in Figs. 4 and 6, said slots acting as firing ports. The attaching nut 14 is provided interiorly thereof with a shoulder 18 adapted to lie below the bottom shoulder of the enlargement 11 on the insulating body 10, and between the bottom shoulder of the enlargement 11 and the internal shoulder 18 of the attaching nut is interposed a washer 19 composed of asbestos or other non-combustible material. A similar washer .20 of asbestos or other non-combustible material is positioned upon the upper shoulder of the enlargement 11, said washer 20 being compressed by screwing a gland 21 into a female thread provided in the upper part of the attaching nut 14, whereby the gland 21 operates to compress the washers 19, 20 between the enlargement 11 of the insulating body, the shoulder 18 of the attaching nut and the gland, so that the attaching nut and the insulating body are coupled rigidly by a gas-tight connection.

Extending centrally through the insulating body 10 is a metal sleeve 22, the external diameter of which sleeve is slightly less than the internal diameter of the longitudinal opening provided in the body 10. The lower part of the metal sleeve 22 is enlarged to form a foot flange 23, the latter being in opposing relation to the internal shoulder 12 near the lower end of the body 10. Between the foot flange 23 of the metal sleeve and the internal shoulder 12 of the insulating body is interposed a gasket 24 composed of asbestos or other non-combustible material, whereby the metal sleeve and the insulating body are so positioned as to produce a gastight joint at the bottom part of the spark plug. The lower part of the metal sleeve is provided with a tapering opening 24 constituting a seat for a tapering collar 25, the latter being provided on a rod 26 which constitutes one of the electrodes of the spark plug. The rod 26 is composed of good electrical conducting metal, and it extends practically the full length of the spark plug, the lower part of said electrode rod 26 extending to and within the ring 16, as shown in Fig. 1, whereas the upper part of the rod 26 extends well above the insulating body 10. For the major part of its length the electrode rod 26 is circular in cross section, but the upper part ofthis electrode rod is fiattened so as to be square or rectangular in cross section, as indicated at 27, a shoulder 28 being provided on the rod intermediate the circular portion and the square portion thereof. It is apparent that the collar 25 is formed on or attached to the electrode rod 26 intermediate the ends of said rod; further, that the collar 25 is adapted to fit accurately into and against the surface of the seat 24 at the lower extremity of the metal sleeve 22, for which purpose the collar 25 and the seat 24 are preferably ground into each other, and that the collar 25 operates as a valve in closing the metal sleeve 22 against the leakage of gas from the engine. As will appear presently, the electrode rod 26 is under the tension of a spring 29 the primary function of which is to retain the collar 25 in close contact with the seat 24.

The ring 16 constituting one of the spark gap terminals is formed on its inner edge to produce a cam surface 30 terminating in an abrupt shoulder 31, as shown clearly in Figs. 4 and 6, the radius of said cam surface 30 increasing progressively from one corner of the shoulder 31 to the other corner thereof. The lower extremity of the elec trode rod 26 terminates in the plane of the cam-shaped ring terminals 16, said rod being centrally positioned within the tubular lower part of the attaching nut 14 and being concentric with the circle forming the outer surface of the ring-shaped terminal 16. Said lower extremity of the electrode rod 26 carries the other spark gap terminal 32,

the same being shown as a finger extending radially from the rod 26, which finger-like terminal 32 is positioned" in the same plane as the cam-shaped ring terminal 16. The terminal 32 is composed of platinum or a platinum alloy, or any metal or alloy appropriate for the purpose, and this terminal 32 is attached in any suitable way to the lower part of the rod. As shown, the terminal 32 extends radially from the rod so that its free end is opposite to the cam surface 30 of the ring-like terminal 16, the position of the terminal 32 with respect to the camsurface terminal 33 determining the length of the spark gap.

The metal tube or sleeve 22 extends upwardly from the insulating body 10, the upper protruding part of said tube or sleeve being externally threaded at 33.

A member 34 is screwed on the threaded part of the sleeve or tube so as to have fixed relation to the tube or sleeve and to the insulating body 10. The lower part of the member 34 is recessed at 35 for the purpose a of receiving the upper end portion of the insulating body 10, said recessed lower part of the member 34 receiving, also, a packing 36 composed of asbestos or other suitable material, which packing is compressed between the member 34 and the body 10 by screwing said member 34 upon the sleeve or tube. The member 34 is provided on its upper surface with a series of ratchet teeth 37,

as shown more clearly in Fig. 2, and cooperating with the fixed member 34 is a shiftable member 38, the same being provided with a depending tooth 39, the latter being adapted for engagement with any one of the series of teeth 37 on the fixed member 34., although if desired the member 38 may be provided with more than one tooth for engagement with the ratchet teeth 37 of fixed member 34. The member 39 is fitted loosely on the upper round part of the electrode rod 26, so that this member can be turned in one direction relatively to the rod and the member 34, the engagement of the tooth 39 with one of the teeth 37locking the member 38 from movement in a reverse direction, although said member 38 may be lifted with respect to the rod for the tooth 39 to clear the teeth 37 and when in said raised position the member 38 may, of course, be turned in either direction by the operator. The member 38 is provided in the upper surface thereof with a recess 40, within which is positiond a age member 41. The recess 40 in said upper ace of the member 38 is circular, as shown in Figs. 3 and 5, but said upper face of the member 38 is provided with other segmental recesses 42 cut through the material of the member 38 to the exterior surface thereof, whereby the recesses 40, 42 leave upstanding ledges 43 on the top of the member 38, which ledges 43 terminate in shoulders 44, 45, as clearly illustrated in Figs. 3 and 5. The gage member 41 is in the form of a disk provided with lugs 46 extending from diametrically opposite sides thereof, said lugs 46 being positioned for operation in the radial slots 42, so that the lugs will work between the shoulders 44 and 45 of the ledges 43, said shoulders operating as stops in limiting the movement of the gage member 41 within the recessed upper part of the member 38. The gage member .41 is provided with a square or oblong aperture adapted to receive .the corresponding part 27 of the electrode rod 26, and thus the gage member 41 is fitted upon the part 27 of the rod 26 in order that said gage member will turn with the electrode rod. It is apparent that the gage member 41 is fitted loosely on the rod so as to be raised or lowered with the member 38 when it is manipulated by hand, but the gage member 41 fits on the angular part 27 of the electrode rod in a manner to have good electrical contact therewith.

The angular part 27 of the electrode rod 26' extends a suitable distance above the shiftable member 38 and the gage member 41 so as to receive an o erating knob 47, the latter being positioned cess by hand so as to turn the electrode rod when required. Said knob 47 is composed of insulating material of any suitable nature, the lower part of said knob being reduced in width by the formation of a recess 48. The knob is shown as being externally ribbed to afi'ord the lower part of the rod is embedded a metal bushing 49 which is externally threaded so as to be screwed into the knob, and this bushing is provided with an angular opening in order to receive the angular part for convenient ac-',

a good hand-grip. Within knob and the rod, I employ a sleeve 51 composed, preferably, of insulating material and adapted to fit snugly upon the recessed lower part 48 of the operating knob. This sleeve 51 is externall flanged at 52 and in the lower end of t e sleeve is fitted a metallic plate 53, the latter being shown as having contact with the metallic bushing 49 of the knob. The knob 47, the sleeve 51 and the plate 53 are positioned a suitable distance above the member 38 in order to accommodate the springs 29, the latter loosely encircling the angular part 27 of the rod. This spring presses upwardly on the plate 53 and the sleeve 51 so as to exert an upward thrust upon the rod 26 owing to the attachment of the knob 47 to the rod by the cross pin 50, which upward thrust on the rod 26 draws the collar 25 into tight engagement with the seat 24 of the metal sleeve, thus securinga gas-tight connection between the rod {26 and the sleeve 22, but at the same time he rod 26 is free to rotate within the metallic sleeve when the knob 47 is manipulated, and said rod 26 is capable, also, of a limited endwise movement under the action of the spring 29 in order to seat the collar 25 in the tube 22. Another function of the spring 29 is to exert pressure upon a circuit terminal 54, the latter being of any usual type, so that its slotted end may beintroduced around the angular part 27 of the electrode rod when said circuit terminal 54 is in metallic and electrical contact with the gage member 41. A clamping member 55is fitted loosely on the angular part of the rod so as to be interposed between the circuit terminal 54 and the spring 29, said spring 29 being seated at its lower end directly upon the clamping member 55 for the purpose of pressing said clamping member 55 against the circuit terminal 54, whereby the required electrical contact is secured between said circuit terminal 54 and the gage member 41.

The operation is as follows:-

The plug is attached to the engine cylinder by screwing the threaded part 15 of the attaching nut 14 into the proper aperture, thus introducing the spark gap terminals 16, 32 within the cylinder. The circuit terminal 54 is thrust between the gage member 41 and the pressure plate 55, thus positioning the terminal 54 into metallic contact with the gage member 41, and the spring 29 acts to retain the partsin the desired electrical conmotion. The knob 47 is turned in order to impart rotative movement to the electrode rod 26 and position the terminal 32 in spaced relation to the coeperating terminal 16, substantially as shown in Fig. 4, in which position the gage member 41 occupies such a relation to the-upstandingledges 43 that the lugs 46 are in contact with the shoulders 44, as shown in Fig. 3. It is apparent that current flows through the terminal 54, the gage member 41, the rod 26, the spark gap terminals 16, 32 and jumps across the space separating the terminal 32 from the terminal 16, whence the'current is grounded through the engine in the ordinary way. Should carbon accumulate on the cam surface 30 of the terminal 16 and upon the terminal-32 so as to interfere with the proper action of the engine, the operator may turn the knob 47 and rod 26 for the terminal 32 to sweep the surface 30 of the terminal 16, thus providing means for mechanically eliminating the carbon by a relativemovement of the terminal 32 to the terminal 16. The required manipulation of the parts is possible owing tothe employment of the knob 47. In this connection, the gage member 41 serves an important function. WVhen the knob and the rod are turned in one direction, the lugs 46 of the member 41 travel in the segmental slots 42 of the member 48 until said lugs 46 strike the shoulders 45, thus arresting the rotative movement of the knob, the rod and the terminal 32, but after the carbon shall have been wiped from the terminals, the

operator should, of course, restore the parts to their former positions, at which time the member 41 rotates with the rod so that the lugs 46 will again contact with the shoulders 44, thereby restoring the terminal 32 into the predetermined relation to the surface 30 of the terminal 16. By this manipulation of the parts it is possible to remove the carbon from the terminals and restore said terminals in order to obtain a spark gap of definite length. It is apparent that each spark plug may be manipulated and ad justed in the manner described to secure uniformity in the spark gaps of all the plugs.

The mechanism described serves anotherimportant function for the reason that provision is made for obtaining spark gaps of predetermined length in order to compensate for a reduction in the operative length of the terminal 32 owing to 'the action on said terminal of the heat developed in the operation of the engine.

It has been stated that the terminal 32 when the engine is in service for a substantial length of time is liable to, become partly burned away owing to the high. heat generated in the operation of the engine, such burning away of the terminal 32 resulting in a decrease of the operative length thereof and consequently in aspark gap the length decreased length of the terminal 32, the operator turns the knob 47 and with it the' member 41 until the lugs 46 of said member are in contact with the shoulders 45, but as the terminal 32 is decreased in length it is apparent that this shorter terminal will not contact with the surface 30 of the terminal 16 when the lugs 46 engage the shoulders 45. Under these conditions the operator continues the turning movement of the'knob 47 and rod 26 so that the member 38 will be turned by the pressure of the lugs 46 against the shoulders 45, and as the turning movement continues the tooth 39 of the member 38 will slip past one or more teeth 37 of the member 34 until the terminal 32 contacts with the surface 30 of the terminal 16, all of which is indicated quite clearly in Figs. 5 and 6. Now the operator should turm the knob 47 in an opposite direction, at which time the member 41 and the rod 26 will turn with the knob until the lugs 46 again engage with the shoulders 44, thus restoring a terminal 32 of shorter length to a predetermined relation to the terminal 16 so as to obtain a spark gap the length of which gap in one plug is equal to the length of the spark gaps in other plugs.

Having thus fully described the invention,

what I claim as new, and desire to secure by whereby a decrease in the operative relation of one terminal to the other may be compensated for and the shiftable terminal be restored by a reverse movement to obtain a spark gap of predetermined length.

2. In a spark plug, a plurality of terminals one of which is provided with a cam surface, in combination with means for shifting one terminal relatively 'to the other, means for stopping the movement in either direction when shifting the terminal as aforesaid, and means yieldable to the action of the stopping means when the shiftable terminal is moved in one direction and beyond a predetermined point.

3. In a spark plug, the combination of a cam-shaped terminal, a second terminal rotatable with respect to the cam surface of the first terminal and adapted to have wiping contact therewith for the removal of carbon deposits, means for stopping the turning movement of the second terminal after it shall have been shifted into wiping contact with the first terminal whereby the second terminal may be returned to its initial position with accuracy so as to result in a spark gap of definite width, means for operating the second terminal, and means yieldable to the action of the stopping means when the second terminal is moved in one direction, said yieldable means operating for the second terminal to move beyond the position permitted by the stopping means and said yieldable means and the stopping means permitting the second terminal to be restored by a reverse movement to a normal position for establishing a spark gap of predetermined length.

4. In a spark plug, the combination of a terminal provided with a cam surface, a second terminal rotatable relatively to said cam surface so as to have wiping contact therewith, means for shifting the second terminal, stopping means for limiting the turning movement of the second terminal in either direction, and means operable when the second terminal is decreased in length to permit a turning movement thereof through a longer are than that permitted by said stoppmg means.

5. In a spark plug, the combination of a cam-shaped terminal, an electrode provided with a second terminal positioned for contact with said cam surface, means for imparting rotative movement to said electrode, stopping means for limiting said rotative movement in either direction to an arc of definite length, and means yieldable to the rotative movement of said electrode upon a decrease in the operative length of the second terminal to permit a further rotative movement of said second terminal until it shall have contact with the cam surface.

6. In a spark plug, the combination of a cam-shaped terminal, an electrode provided with a second terminal positioned for contact with said cam-surface, means for imparting rotative movement to said electrode,

stopping means for limiting said rotative movement in either direction to an arc of definite length, and yieldable means coopcrating with the stopping device for permitting. a rotative movement in one direction through an arc of greater length upon a decrease in the operative length of the second terminal, said yieldable means and the stop ping device cooperating to limit a backward rotative movement of said second electrode through an arc of the aforesaid definite length.

7. In a spark plug, the combination of a cam-shaped terminal, an electrode provided with a second terminal positioned for contact with said cam surface, a fixed stop member, a second stop member cooperating with the fixed stop member so as to be normally stationary relatively thereto and adapted under certain conditions to be shifted with respect to said fixed member, means for turning the electrode, and a gage member turnable with the electrode and movable in either direction relatively to the second stop member through an arc of definite length.

8. In a spark plug, the combination of a cam-shaped terminal, an electrode provided with a second terminal positioned for contact with said cam surface, a fixed stop member, a

second stop member having locking relation to the first stop member, a gage member movable through an arc of given length relatively to the second stop member, said gage member being operated by a rotative movement of the electrode, and means for rotating the electrode, said gage member and the second stop member being movable relatively to the first stop member through an arc eX- ceeding in length that of the aforesaidarc of definite length when the second terminal is decreased in length.

9. In a spark plug, the combination of a cam-shaped terminal, an electrode provided with a second terminal positioned for contact with said cam surface, a fixed stop I member, a second stop member locked to the first stop member, a gage member rotatable with said electrode, said gage member being turnable with the electrode in either direction and through an arc of definite length, whereby the second electrode may be rotated in one direction and then reversed to a given position relatively to the cam surface, and means for rotating the electrode, said gage member and the second stop member being yieldable relatively to the first stop member so as to be movable in one direction with the second terminal through an arc the length of which is increased with respect to that of the arc of definite length.

10. In a spark plug, the combination of a plurality of terminals, means for shifting one terminal relatively to the other, stopping devices whereby under one condition the shiftable terminal may be moved a definite distance in either direction, and means cooperating with the stopping devices for permitting a movement of said shiftable terminal in one direction for an increased distance and in an opposite direction for the first named definite distance.

r 11. In a spark plug," the combination of an insulating body, an attaching member provided with a cam-shaped terminal, an electrode rotatable in said body, a second terminal carried by the electrode and positioned for contact with said cam-shaped. terminal, means for rotating the electrode, stopping devices cooperating with the nsulating body and with the electrode for limiting the turning movement in either direction of said electrode and the second terminal, and means operated by the stopping devices for permitting the electrode and second terminal to be shifted in one direction beyond the normal position permitted by said stopping devices.

12. In a spark plug, the combination of an insulating body, an attaching member provided with a cam-shaped terminal, an electrode slidable and rotatable within said body, means for securing a gas-tight connection between the electrode and the body, a second terminal carried by the electrode, means for rotating the electrode, stopping means for arresting Within definite limits the back and forth rotative movement of the electrode and the second terminal, and means yieldable to the action of the stopping means when the second terminal and electrode are moved in one direction beyond the definite limit permitted by the action of the stopping means,

13. In a spark plug, the combination of an insulating body, an attaching member provided with firing ports and with an internal cam surface constituting a spark gap terminal, an electrode rotatable in the body, a second terminal on the electrode, means for rotating the electrode at will, stopping devices for limiting the rotative movement of the electrode and the second terminal through an arc of definite length, and means yieldable to the action of the stopping devices for permitting the second terminal to be moved through an arc the length of Which exceeds the are permitted by said stopping devices.

14. In a spark plug, the combination of an insulating body, an attaching member provided with a cam-shaped terminal, an electrode provided with a second terminal, afiXed stop member on the body, a second stop member loose With respect to the electrode, a gage member rotatable With the electrode and cooperating with the second stop member for limiting the rotative move- .ment of the electrode through an arc of given length, a knob attached to the electrode for turning it at will, a spring acting on the electrode, and a circuit terminal clamp pressed by the spring for securing electrical contact of a circuit terminal With the electrode and the gage member.

15. In a spark plug, the combination with a terminal, of an electrode provided With a second terminal, a fixed stop member, a shiftable stop member normally locked by the first stop member, and a gage member movable With the electrode and adapted to be arrested in its movement by the second stop member, said gage member and the second stop member being operable with the electrode so as to compensate for an increase in the length of thespark gap between said terminals.

In witness whereof, I have hereunto subscribed my name.

LAWRENCE P. MGKEONE. 

